The present invention relates to a wafer box for receiving and holding large numbers of single-crystal semiconductor wafers, in particular, compound single-crystal wafers.
Single-crystal semiconductor wafers must be maintained separated from one another when being stored or transported. Silicon wafers are generally circular in shape and standardized in size, and hence it is possible to standardize the shape and size of containers for storing silicon wafers. A wafer box such as shown in FIG. 1 is known for this purpose.
With reference to FIG. 1, semicircular thin grooves are formed at regular intervals on both side surfaces in the longitudinal direction of a wafer box body of a rectangular parallelpiped shape having an opening at the upper part. A resilient grooved supporting member is provided at the bottom of the body.
A wafer can be inserted into each of the grooves, the side parts of the wafer being held by the grooves and the lower part being supported by the grooved supporting member. The upper part of the wafer is supported by a resilient grooved supporting member located on the lower surface of a closure covering the wafer box body. The illustrated wafer box is widely used in the case of silicon wafers of standardized shape and size as mentioned above. As silicon wafers have some inherent strength, little damage occurs during storage or transportation of the wafer box.
Recently, various kinds of compound semiconductor single-crystal wafers have been developed. These compound wafers generally have a much lower mechanical strength than silicon wafers. Furthermore, the processes and conditions for growing various crystals are different due to the different components of the crystals, and the conditions for cutting an ingot into wafers are also different. Therefore, the size of compound wafers is not yet standardized and wafers of various shapes and sizes are currently being manufactured. In addition, a compound wafer often requires a higher degree of cleanliness than a silicon wafer. Accordingly, it has become difficult to use a conventional wafer box intended for use with silicon wafers with compound wafers. That is to say, it has been found that it is necessary to provide wafer boxes corresponding to the specific shapes and sizes of the various wafers. Nevertheless, a significant amount of damage can still occur. This has been dealt with by using individual thin, dish-shaped containers, which practice is inefficient and costly.
Thus, it is an object of this invention to provide a wafer box which can receive wafers of different shapes and sizes but with which the wafers are not damaged during receiving, taking out and transportation, even if the wafers received in the box are compound semiconductor crystal wafers.